Light signal



Aug. 11, 1925. 1,548,984

S. M. DAY

LIGHT S IGNAL Filed Oct. 24. 1921 Patented Aug. 11, 1925.

UNITED STATES PATENT OFFICE.

SALISBURY M. DAY, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF GATES, NEW YORK,

A CORPORATION OF NEW YORK.

LIGHT SIGNAL.

Application filed October 24, 1921. Serial No. 610,033.

To all whom it may concern:

Be it known that I, SALISBURY M. DAY, a citizen of the United Statesof America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Light Signals, of which the following is a specification.

This invention relates to light signals for railway signaling purposes, and more particularly to light signals having a distlnc tive indication insignia, other than merely the color of the light emitted.

In railway signaling there are occasions where it is desirable to give distinctive signals that can easily and clearly be distinguished from the usual color signals used for automatic block and interlocklng signal indications. For example, in connection with interlocking signals it is frequently desired to be able to give what is commonly termed a call "on signal; in other instances, it is desired to give a distinctive signal signifying take siding; and it is also desirable to give distinctive indications which are con tinuous in character for a marker light, or for signs, such as safe speed, Whistle, yard limits, etc.

Since the indication should be visible both during the day time as well as at night, light signals are well adapted for this purpose. In order, h0wever,to distinguish them from the regular color light signals used as block and interlocking signals, and also obtain the requisite number of different indications, it is desirable to provide a signal structure which is adaptable to give any one of a wide variety of indications, other than mere color, which are distinctive in character. Also, a distinctive signal of this kind should be penetrating to an extent to be visible at a considerable distance under unfavorable weather conditions, such as fog, snow, or the like.

With the above and other considerations in mind, the principal object and purpose of the present invention is to provide a light signal which will give an indication by letter,.word sign, symbol or the like, either of the same or different colors. An ancillary purpose of the present invention is to provide an efficient unit for giving such an 1ndication. t

Other objects and advantages will appear as the description progresses, and-"the novel features of the invention will be pointed out in the appended claims.

In describing the invention in detail, reference will be made tothe accompanying drawings, in which Fig. 1 shows a sectional elevation of the device embodying the present invention;

Fig. 2 is a front elevation of the device;

and Fig. 3 is a sectional view of the device taken on the line 33 Fig. 1, viewed in the direction of the arrows.

Referring to the accompanying drawing,

. the specific embodiment of the present invention comprises a casing 1, preferably made of castiron,

having a large central opening in the front Wall and an open back which is closed by a hinged door 2. This door is provided with a channel adjacent its outer edge containing a gasket 8 arranged to bear against the edge of the casing; and a suitable spring hasp fastener 4: serves to fasten the door 2. Near the top the door is provided with a ventilatin opening having the outside or convex surface and is smoothon the inside or concave surface, and is placed very near a concentrated light source, thus collecting a very large part of the light and converging the same on the outer lens 8. The outer lens 8 is stepped on the inside and smooth on the outside and serves to converge the light into a beam of the desired spread. The large lens 8 is held in place by a bezel or. retaining ring 9 fastened to the lens barrel 6 by cap screws 10, this ring 9 being provided with a semi-circular flange 11 having a shield or sun shade 12 bolted thereto. The small lens 7 is held in place by a retaining ring 13 fastened to the lens barrel by screws 14. This retaining ring 13 has two downwardly extending arms 15 provided-with slots (see Fig. 3) through which pass bolts 16 adjustably securing a pair of angle brackets 17. To these brackets 17 a shelf 18 is adustably fastened by bolts 19 passing through slots in said brackets 17 (see Fig. 1). A lamp socket or receptacle is mounted on the shelf, and the socket 21.

shelf is adjusted during manufacture to bring the porcelain .block 20 and the bayonet socket member 21 of the receptacle in a fixed position with respect to the refilaments will come in the proper place,

thereby obviating the necessity of making a special adjustment each time a burnt out lamp is replaced.

In order to give a distinctive indication, a transparent-outline of a suitable insignia or indicia, such as the letter A, is formed on an opaque background 24 on the surfaceof the inner lens; or, if desired, the letter may be opaque on a transparent background. g

The letter or other insignia is preferably formed on the inner lens by placing a piece of paper, or the like, on the inner lens having the shape to produce the desired indicia on the outer face of the lens 8, and then sand blasting this inner face to roughen the remainder of the surface around the letter. A suitable paint of a color slightly darker than the glass but opaque in character, is

is then applied to the roughened surface, forming an opaque background 24 for the letter. The color of this paint is selected so that the letter will not be discernible when the lamp is not lighted, due to the similarity of the colors of the lens and paint. One particular combination of colors, tried by actual test and found satisfactory, consists of a red lens and an opaque paint of maroon color. The color of the paint used with a particular colored lens is also to a certain extent dependent on the color of the inner walls of the casing. The specific colors above mentioned were selected for use in connection with a casing having its inner walls darkened.

The indicia is preferably formed on the inner surface of the inner lens because the inner surface is smooth, thereby making the application of the opaque paint or other substance by which the outline of the indicia is formed easier, and further thereby protecting such paint from exposure to weather.

When the lamp is lighted, a clear and arrestive image of the letter or other indicia is formed by'the light transmitted through the transparent outline of the letter. This image will be the color of the inner lens 7, and will be magnified-to appear as if it were the full size of the outer lens 8.

Distinctive aspect signals are sometimes intended to give a continuous and permanent indication, as in the case of marker lights, for example, while in other instances the indication is controlled in some suitable manner and should not be given unless conditions warrant, as for example, in the case of a call on signal. The present invention contemplates the provision of a signal structure adaptable for both purposes. Where the signal indication should be given only at a proper time, it is obvious that the signal must be constructed so that it will not give a false or so-called phantom signal.

uch phantom signals are caused by light from some outside source, such as bright sunshine or a locomotive headlight, which shines into the signal and is reflected or diffused back, giving the signal the appearance of being lighted. In order to avoid any difficulty with such phantom signals, the inside of the signal casing should be dark, and reflectors should be avoided. Where the signal is used. to'give a continuous indication, that is, is to be permanently illuminated, it is not necessary to consider the possibility of phantom indications, because even if such an indication. should be given when the lamp is burnt out, the correct and proper information would be communicated.

Consequentl when a distinctive indication signal embo ying the present invention is to be used for a marker light, or the like, a suitable reflector may be used so as to utilize as much of the light from the light source as possible and intensify the indication. For this purpose, aspherical mirror 25 with its center of curvature coinciding with the point at which the luminous center of the lamp filament 22 is located, may be suitably attached to the door or walls of the casing behind the lamp. This mirror or reflector 25 preferably extends through a solid angle large enough to reflect all of the light that can be transmitted through the inner lens 7 when reflected through the focus of the lens combination. While the mirror 25 may be constructed and supported in any suitable way, in the particular arrangement shown, the mirror is made of glass with its outer convex surface'silvered and suitably protected; and this mirror 25 is held in place by a bezel ring 26 fastened to the door 2.

The signal, casing 1 is adjustably supported on a base B having a socket 27 adapted to receive a signal pole of the usual construction (not shown). This base B is provided at the middle with a boss 28, which is adapted to rest in a beveled opening (see Fig. '1) located both in the bottom and also the top wall of the casing 1, thus forming a ball and socket connection. The base B and casing 1 are held together by four bolts29,

The top of the casing 1 is finished by a 1 suitable cover plate 30.

Having shown and described one specific embodiment of the invention, and having pointed out several ways ii -which it may be employed, I desire to; have it understood that this does not exhaust the idea of means underlying the present invention, or its mode of operation.

What I claim is 1. A light signal for railway signaling purposes Immune to phantom indications and capable of produclng an indicia visible at a considerable distance comprisin a casing having its inside walls darkene an inner and an outer lens in said casing op: tically constructed so that light emitted from a point near the inner lens will be converged into a light beam having a small angle of spread, a concentrated source of light at said point, and an opaque medium provided on the inner face of said inner lens to produce a virtual image of an 'indicia on the outer face of said outer lens.

2. A color light signal for railway signaling purposes immune to phantom indications and capable of producing a distinctive character signal of colored light visible at a considerable distance comprising, a casing having an opening and having its internal walls darkened, a compound lens unit in said opening consisting of an outer large clear lens and an inner small colored lens,

said lenses being constructed .so that light emitted from a point near the inner lens will be directed on the outer lens and will then be converged into a light beam havin a small angle of spread an opaque medium of a color similar to that of the inner lens provided on said inner lens to form a distinctive character, similar to that of the character will be projected upon said outer clear lens when ight is emitted from said point and the outer lens will appear colorless when no light isemitted therefrom; i

3. A light signal for railway signaling purposes adapted to give a distinctive character or sign indication of colored light at a distance, the combination with a light projecting unit including an electric lamp having a concentrated filament, and an optical device comprising an outer clear lens and an inner colored lens, these lenses 'bewhereby a colored image ing optically constructed so'that light emitted from said filament will be concentrated by the inner colored lens upon the outer clear lens-which will concentrate the light into a beam having a small angle of s read, said inner lens having portions t ereof roughened and covered with an opaque medium, whereby a solid angle of colored light defining the desired sign or character will be projected from said optical device.

4. A distinctive light si al for railway signaling purposes comprising, a casing having an opening in the front wall, a lens barrel in said opening, a concentrated source of light, in said casing, a large lens in the outside end and a small lens in the inside end of said barrel, an opaque medium on part of said inner small lens forming a character, said lenses being constructed so that light radiated from said source will cast an enlarged indicia on said large lens, and

'means extending from the outside ofsaid casing to shield said large lens from foreign light rays. In testimony whereof I hereto aflix my signature.

SALISBURY M. DAY. 

